There are readers who actually believe that an author writing in the first person is writing about his own experience. When you’ve stretched your imagination to the limits to come up with a plausible account of a character’s inner and outer lives, and then your reader thinks that all you’ve done is write down what actually happened to you, this can be very frustrating.
It’s undeniable that an author must be capable of thinking of the things he writes about his characters. But it’s a great mistake to assume that in describing them he is invariably describing himself.
An author has to draw on everything he knows about himself and about other people, extending his imagination into the corners of his characters’ minds through his powers of intuition and insight to make them real and believable even if they are nothing like him. That is part of the genius of the great authors. They reveal our common humanity, but they also invent what they haven’t personally experienced, and we find it believable.